<!DOCTYPE HTML>
<html>
<head>
    <meta charset="UTF-8">
    <title>My WebSocket</title>
</head>
<body>
<label for="userId">用户ID:</label><input type="number" id="userId"/>
<button onclick="conectWebSocket()">连接WebSocket</button>
<button onclick="closeWebSocket()">断开连接</button>
<hr />
<br />
<label for="text">消息：</label><input id="text" type="text" />
<label for="receiver">接受者ID：</label><input id="receiver" type="number" />
<button onclick="send()">发送消息</button>
<div id="message"></div>
</body>
<script type="text/javascript">
    var websocket = null;
    function conectWebSocket(){
        var userId = document.getElementById("userId").value;
        console.log("userId:" + userId)
        if(userId === ""){
            alert("请输入用户ID");
            window.close();
        }
        //判断当前浏览器是否支持WebSocket
        if ('WebSocket'in window) {
            websocket = new WebSocket("ws://127.0.0.1:8080/websocket/" + userId);
        } else {
            alert('Not support websocket')
        }
        //连接发生错误的回调方法
        websocket.onerror = function() {
            setMessageInnerHTML("error");
        };
        //连接成功建立的回调方法
        websocket.onopen = function(event) {
            console.log(event)
            setMessageInnerHTML("Loc MSG: 成功建立连接");
        }
        //接收到消息的回调方法
        websocket.onmessage = function(event) {
            setMessageInnerHTML(event.data);
        }
        //连接关闭的回调方法
        websocket.onclose = function() {
            setMessageInnerHTML("Loc MSG:关闭连接");
        }
        //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
        window.onbeforeunload = function() {
            websocket.close();
        }
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket() {
        websocket.close();
    }

    //发送消息
    function send() {
        //获取输入的文本信息进行发送
        var message = document.getElementById('text').value;
        console.log("message:" + message)
        var receiver = document.getElementById('receiver').value;
        console.log("receiver:" + receiver)
        var socketMsg = {content:message,receiver:receiver};
        console.log("socketMsg:" + socketMsg)
        websocket.send(JSON.stringify(socketMsg));
    }
</script>
<!--样式-->
<style>
    #message{
        margin-top:40px;
        border:1px solid gray;
        padding:20px;
    }
</style>
</html>